Image bilevel thresholding based on multiscale gradient multiplication
Yaobin Zou · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2012
This paper introduces a novel global thresholding approach that exploits the product of gradient magnitude (PGM). The PGM of an image is obtained by multiplying the responses of the first derivative of Gaussian (FDoG) filter at three adjacent space scales. The output threshold is selected as the one that maximizes a new objective function of the gray level variable t . The objective function is defined as the ratio of the mean PGM values of the boundary and nonboundary regions in the binary image obtained by thresholding with variable t . Through analysis of 35 real images from different application areas, our results show that the proposed method can perform bilevel thresholding on the images with different histogram patterns, including unimodal, bimodal, multimodal, or comb-like shape. Its segmentation quality is superior to five popular thresholding algorithms.